1. Field of the Invention
The present invention relates to an air-permeable cushion having a three-dimensional net and suited for use in seats, beds or the like.
2. Description of the Related Art
Conventional seats or beds generally include a pad material placed on a frame and covered with a skin, and some of them also include spring members for enhancing the cushioning characteristics. Such seats or beds still involve room for improvement in air permeability or in heat-radiating properties, and they are mostly thick, heavy and costly.
Recently, a relatively light net-shaped cushion structure having a superior air permeability has been proposed.
Such a net-shaped cushion structure can be used for a cushioning member such, for example, as a floor cushion only by treating side edges thereof. It can be also used for a seat cushion by fitting anchoring members thereto after the side edge treatment and by engaging the anchoring members with a frame of a seat.
However, where the net-shaped cushion structure is used for the seat cushion, relatively large molded articles made by an injection method are generally used for the anchoring members. Accordingly, a relatively large molding machine is needed, resulting in an increase in initial cost.
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide an inexpensive cushion having a three-dimensional net that has a superior durability and can be readily and positively mounted to a seat frame or the like.
In accomplishing the above and other objectives, the cushion according to the present invention includes a three-dimensional net, a plurality of metallic fastening members attached to the three-dimensional net on opposite sides thereof, and two resinous frames attached to the opposite sides of the three-dimensional net, respectively. The plurality of metallic fastening members are sandwiched between the two resinous frames and the opposite sides of the three-dimensional net, and the two resinous frames together with the plurality of metallic fastening members are joined to the three-dimensional net by vibration welding.
This construction enables the three-dimensional net to be positively secured to, for example, a seat frame with the use of the fastening members, resulting in an increase in durability. Both the fastening members and the resinous frames are relatively inexpensive, and the fastening members can be readily attached to the seat frame. Furthermore, the metallic fastening members, which cannot be solely welded to the three-dimensional net, can be secured to the side portions of the three-dimensional net by making use of the resinous frames, making it possible to provide an inexpensive cushion.
Advantageously, each of the plurality of metallic fastening members has a recess formed at a welded portion on each side thereof. This recess acts to increase the joining strength obtained by the vibration welding, resulting in an increase in durability.
Again advantageously, each of the plurality of metallic fastening members has a plurality of projections formed therewith along the recess, and at least one of them is bent at right angles so as to bite into the resinous frame, thereby facilitating the positioning of the fastening members and increasing the joining strength.
Conveniently, the cushion further includes at least one belt attached to the three-dimensional net. Not only the weight of a cushion occupant but a load inputted to the cushion from outside can be supported by both the three-dimensional net and the belt, thus further increasing the durability.